scholarly journals Studying insect diversity in the tropics

1999 ◽  
Vol 354 (1391) ◽  
pp. 1811-1824 ◽  
Author(s):  
H. C. J. Godfray ◽  
O. T. Lewis ◽  
J. Memmott
Keyword(s):  
Food Webs ◽  
Trophic Structure ◽  
Community Dynamics ◽  
Experimental Studies ◽  
Leaf Miner ◽  
Insect Diversity ◽  
Insect Community ◽  
Structure Of Communities ◽  
Modern Ecology ◽  
The Tropics

Understanding the extent and causes of insect diversity in the humid tropics is one of the major challenges in modern ecology. We review some of the current approaches to this problem, and discuss how future progress may be made. Recent calculations that there may be more than 30 million species of insect on earth have focused attention on the magnitude of this problem and stimulated several new lines of research (although the true figure is now widely thought to be between five and ten million species). We discuss work based on insecticidal fogging surveys; studies of herbivore and parasitoid specificity; macroecological approaches; and the construction of food webs. It is argued that progress in estimating insect diversity and in understanding insect community dynamics will be enhanced by building local inventories of species diversity, and in descriptive and experimental studies of the trophic structure of communities. As an illustration of work aimed at the last goal, we discuss the construction and analysis of quantitative host–parasitoid food webs, drawing on our work on leaf miner communities in Central America.

scholarly journals Food Chains and Food Webs in Aquatic Ecosystems

2020 ◽  
Vol 10 (14) ◽  
pp. 5012
Author(s):  
Ihn-Sil Kwak ◽  
Young-Seuk Park
Keyword(s):  
Food Webs ◽  
Species Interactions ◽  
Aquatic Ecosystems ◽  
Empirical Studies ◽  
Experimental Studies ◽  
Environmental Dna ◽  
Gut Contents ◽  
Food Chains ◽  
Energy Flows ◽  
Structure Of Communities

Food chains and food webs describe the structure of communities and their energy flows, and they present interactions between species. Recently, diverse methods have been developed for both experimental studies and theoretical/computational studies on food webs as well as species interactions. They are effectively used for various applications, including the monitoring and assessment of ecosystems. This Special Issue includes six empirical studies on food chains and food webs as well as effects of environmental factors on organisms in aquatic ecosystems. They confirmed the usefulness of their methods including isotope, DNA-barcoding with gut contents, and environmental DNA for biological monitoring and ecosystem assessment.

scholarly journals Upstream trophic structure modulates downstream community dynamics via resource subsidies

2017 ◽  
Vol 7 (15) ◽  
pp. 5724-5731 ◽  
Author(s):  
Eric Harvey ◽  
Isabelle Gounand ◽  
Chelsea J. Little ◽  
Emanuel A. Fronhofer ◽  
Florian Altermatt
Keyword(s):  
Trophic Structure ◽  
Community Dynamics ◽  
Resource Subsidies

scholarly journals Biodiversity and trophic ecology of hydrothermal vent fauna associated with tubeworm assemblages on the Juan de Fuca Ridge

2018 ◽  
Vol 15 (9) ◽  
pp. 2629-2647 ◽  
Author(s):  
Yann Lelièvre ◽  
Jozée Sarrazin ◽  
Julien Marticorena ◽  
Gauthier Schaal ◽  
Thomas Day ◽  
...  
Keyword(s):  
Food Webs ◽  
Hydrothermal Vent ◽  
Trophic Structure ◽  
Juan De Fuca Ridge ◽  
Small Scale ◽  
Ecological Niches ◽  
Primary Role ◽  
Fuca Ridge ◽  
Juan De Fuca ◽  
Successional Stages

Abstract. Hydrothermal vent sites along the Juan de Fuca Ridge in the north-east Pacific host dense populations of Ridgeia piscesae tubeworms that promote habitat heterogeneity and local diversity. A detailed description of the biodiversity and community structure is needed to help understand the ecological processes that underlie the distribution and dynamics of deep-sea vent communities. Here, we assessed the composition, abundance, diversity and trophic structure of six tubeworm samples, corresponding to different successional stages, collected on the Grotto hydrothermal edifice (Main Endeavour Field, Juan de Fuca Ridge) at 2196 m depth. Including R. piscesae, a total of 36 macrofaunal taxa were identified to the species level. Although polychaetes made up the most diverse taxon, faunal densities were dominated by gastropods. Most tubeworm aggregations were numerically dominated by the gastropods Lepetodrilus fucensis and Depressigyra globulus and polychaete Amphisamytha carldarei. The highest diversities were found in tubeworm aggregations characterised by the longest tubes (18.5 ± 3.3 cm). The high biomass of grazers and high resource partitioning at a small scale illustrates the importance of the diversity of free-living microbial communities in the maintenance of food webs. Although symbiont-bearing invertebrates R. piscesae represented a large part of the total biomass, the low number of specialised predators on this potential food source suggests that its primary role lies in community structuring. Vent food webs did not appear to be organised through predator–prey relationships. For example, although trophic structure complexity increased with ecological successional stages, showing a higher number of predators in the last stages, the food web structure itself did not change across assemblages. We suggest that environmental gradients provided by the biogenic structure of tubeworm bushes generate a multitude of ecological niches and contribute to the partitioning of nutritional resources, releasing communities from competition pressure for resources and thus allowing species to coexist.

scholarly journals Does Altering Local Water Availability for an Invasive Plant (Raphanus raphanistrum) Affect Floral Morphology and Reproductive Potential?

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Natalia Pirimova ◽  
Alison Parker ◽  
Lesley Campbell
Keyword(s):  
Soil Moisture ◽  
Foraging Behavior ◽  
Water Availability ◽  
Community Dynamics ◽  
Invasive Plant ◽  
Floral Morphology ◽  
Insect Community ◽  
Raphanus Raphanistrum ◽  
Anther Length ◽  
Corolla Diameter

Abiotic environmental variation can have dramatic effects on plant floral morphology and nectar or pollen rewards. In response, pollinators may change their foraging behavior and distribution and if pollinators change their foraging behavior or distribution, this could have dramatic effects on the reproductive success of plant populations. To start tackling this problem, we measured the response of floral morphology (corolla diameter, stamen length, and ovule number) of Raphanus raphanistrum to experimental manipulations of field soil moisture. As soil moisture increased, corolla diameter and anther length grew. We expect these changes to provide more visitation rewards for insects in moist conditions. Therefore, water availability influences growth and development of flowers, and may have dramatic effects on insect community dynamics. KEYWORDS: Floral Rewards, Climate, Rain-out Shelters, Flower Morphology, Raphanus raphanistrum, Brassicaceae

scholarly journals What drives interaction strengths in complex food webs? A test with feeding rates of a generalist stream predator

2018 ◽  
Author(s):  
Daniel L. Preston ◽  
Jeremy S. Henderson ◽  
Landon P. Falke ◽  
Leah M. Segui ◽  
Tamara J. Layden ◽  
...  
Keyword(s):  
Food Webs ◽  
Body Mass ◽  
Prey Density ◽  
Scaling Laws ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Interaction Strength ◽  
Feeding Rates ◽  
Predator Prey ◽  
Mass Ratios

AbstractDescribing the mechanisms that drive variation in species interaction strengths is central to understanding, predicting, and managing community dynamics. Multiple factors have been linked to trophic interaction strength variation, including species densities, species traits, and abiotic factors. Yet most empirical tests of the relative roles of multiple mechanisms that drive variation have been limited to simplified experiments that may diverge from the dynamics of natural food webs. Here, we used a field-based observational approach to quantify the roles of prey density, predator density, predator-prey body-mass ratios, prey identity, and abiotic factors in driving variation in feeding rates of reticulate sculpin (Cottus perplexus). We combined data on over 6,000 predator-prey observations with prey identification time functions to estimate 289 prey-specific feeding rates at nine stream sites in Oregon. Feeding rates on 57 prey types showed an approximately log-normal distribution, with few strong and many weak interactions. Model selection indicated that prey density, followed by prey identity, were the two most important predictors of prey-specific sculpin feeding rates. Feeding rates showed a positive, accelerating relationship with prey density that was inconsistent with predator saturation predicted by current functional response models. Feeding rates also exhibited four orders-of-magnitude in variation across prey taxonomic orders, with the lowest feeding rates observed on prey with significant anti-predator defenses. Body-mass ratios were the third most important predictor variable, showing a hump-shaped relationship with the highest feeding rates at intermediate ratios. Sculpin density was negatively correlated with feeding rates, consistent with the presence of intraspecific predator interference. Our results highlight how multiple co-occurring drivers shape trophic interactions in nature and underscore ways in which simplified experiments or reliance on scaling laws alone may lead to biased inferences about the structure and dynamics of species-rich food webs.

scholarly journals Latitudinal gradients in biotic niche breadth vary across ecosystem types

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151589 ◽  
Author(s):  
Alyssa R. Cirtwill ◽  
Daniel B. Stouffer ◽  
Tamara N. Romanuk
Keyword(s):  
Species Richness ◽  
Food Webs ◽  
Niche Breadth ◽  
The Other ◽  
Latitudinal Gradients ◽  
Food Web Structure ◽  
Scaling Relationships ◽  
Web Structure ◽  
Scaling Relationship ◽  
The Tropics

Several properties of food webs—the networks of feeding links between species—are known to vary systematically with the species richness of the underlying community. Under the ‘latitude–niche breadth hypothesis’, which predicts that species in the tropics will tend to evolve narrower niches, one might expect that these scaling relationships could also be affected by latitude. To test this hypothesis, we analysed the scaling relationships between species richness and average generality, vulnerability and links per species across a set of 196 empirical food webs. In estuarine, marine and terrestrial food webs there was no effect of latitude on any scaling relationship, suggesting constant niche breadth in these habitats. In freshwater communities, on the other hand, there were strong effects of latitude on scaling relationships, supporting the latitude–niche breadth hypothesis. These contrasting findings indicate that it may be more important to account for habitat than latitude when exploring gradients in food-web structure.

scholarly journals Moving beyond linear food chains: trait-mediated indirect interactions in a rocky intertidal food web

2017 ◽  
Vol 284 (1851) ◽  
pp. 20162590 ◽  
Author(s):  
Geoffrey C. Trussell ◽  
Catherine M. Matassa ◽  
Patrick J. Ewanchuk
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Predation Risk ◽  
Community Dynamics ◽  
Indirect Interactions ◽  
Positive Interactions ◽  
Food Chains ◽  
Feeding Rates ◽  
Basal Resources ◽  
Crab Predation

In simple, linear food chains, top predators can have positive indirect effects on basal resources by causing changes in the traits (e.g. behaviour, feeding rates) of intermediate consumers. Although less is known about trait-mediated indirect interactions (TMIIs) in more complex food webs, it has been suggested that such complexity dampens trophic cascades. We examined TMIIs between a predatory crab ( Carcinus maenas ) and two ecologically important basal resources, fucoid algae ( Ascophyllum nodosum ) and barnacles ( Semibalanus balanoides ), which are consumed by herbivorous ( Littorina littorea ) and carnivorous ( Nucella lapillus ) snails, respectively. Because crab predation risk suppresses snail feeding rates, we hypothesized that crabs would also shape direct and indirect interactions among the multiple consumers and resources. We found that the magnitude of TMIIs between the crab and each resource depended on the suite of intermediate consumers present in the food web. Carnivorous snails ( Nucella ) transmitted TMIIs between crabs and barnacles. However, crab–algae TMIIs were transmitted by both herbivorous ( Littorina ) and carnivorous ( Nucella ) snails, and these TMIIs were additive. By causing Nucella to consume fewer barnacles, crab predation risk allowed fucoids that had settled on or between barnacles to remain in the community. Hence, positive interactions between barnacles and algae caused crab–algae TMIIs to be strongest when both consumers were present. Studies of TMIIs in more realistic, reticulate food webs will be necessary for a more complete understanding of how predation risk shapes community dynamics.

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